202 INNER CELL MASS EXCHANGE IN SHEEP EMBRYOS

2007 ◽  
Vol 19 (1) ◽  
pp. 218 ◽  
Author(s):  
P. Loi ◽  
K. Matsukawa ◽  
C. Galli ◽  
G. Ptak

The presence of a developmental axis in the mammalian oocyte/embryo is still a controversial issue (Plusa 2005 Nature 17, 391–395). However, pre-established or not, mammalian blastocysts display a clear asymmetry with distinct embryonic and abembryonic poles. The present emphasis on ‘mosaic’ development in mammalian embryos is in contrast with classical embryological work, aimed at cell lineage analysis, where manipulation procedures severely perturbed the natural blastocyst asymmetry (Gardner 2001 RBM Online 4, 46–51). However, all of the experimental work thus far has been carried out on mouse embryos. In our work, we designed experiments to determine whether sheep embryos subjected to inner cell mass (ICM) transfer retain normal developmental competence. In vitro-derived sheep blastocysts (Ptak et al. 2003 Biol. Reprod. 69, 278–285) were manipulated with a Narishige micromanipulator fitted to a inverted Nikon microscope. ICMs were dissected with a blade, and the trophoblastic vesicle and ICMs were cultured in SOFaa plus 10% FCS. After re-expansion, trophoblastic vesicles were injected with ICMs by means of a bevelled pipette and cultured overnight with SOFaa plus 10% FCS. From a total of 35 blastocysts used, 25 re-expanded following injection, and 20 of them showed ICMs adherent to the trophoblast. Seven blastocysts were transferred into synchronized ewes 7 days after estrus, and monitored every month with an Aloka linear probe (7–5 MHz; Aloka Co., Ltd., Tokyo, Japan). Twenty-one in vitro-produced (IVP) embryos were transferred as a control. Three ewes receiving ICM-exchanged blastocysts were pregnant at the first scanning, and all delivered normal offspring (two female and one male lamb; weight: 3.54 ± 0.358 kg). These data demonstrate that dramatic alteration of the blastocyst structure does not compromise its developmental potential. Our efficiency in terms of offspring is lower compared with control IVP embryos, and also compared to data obtained in mice (Papaioannou 1982 J. Embryol. Exp. Morph. 68, 199–209), but technical improvements are expected to reduce such a gap. In conclusion, we demonstrated the feasibility of ICM/trophoblastic exchange in sheep blastocysts; these results might have important application for technologies like somatic cell nuclear transfer (SCNT). Common features of SCNT clones are placental abnormalities in early (DeSousa et al. 2001 Biol. Reprod. 65, 23–30) and late pregnancies (Loi et al. 2006 Theriogenology 65, 1110–1121). The transfer of ICM from cloned embryos to normal trophoblastic vesicles, although ineffective in cattle (Murakami et al. 2006 Cloning Stem Cells 8, 51–69), might be worth trying on sheep, a species where post-natal mortality in clones is a serious issue. Table 1.Development to term of manipulated and cloned embryos Part of this work was supported by EUROSTELLS-European Science Foundation.

1993 ◽  
Vol 13 (12) ◽  
pp. 7971-7976
Author(s):  
L M Whyatt ◽  
A Düwel ◽  
A G Smith ◽  
P D Rathjen

Embryonic stem (ES) cells, derived from the inner cell mass of the preimplantation mouse embryo, are used increasingly as an experimental tool for the investigation of early mammalian development. The differentiation of these cells in vitro can be used as an assay for factors that regulate early developmental decisions in the embryo, while the effects of altered gene expression during early embryogenesis can be analyzed in chimeric mice generated from modified ES cells. The experimental versatility of ES cells would be significantly increased by the development of systems which allow precise control of heterologous gene expression. In this paper, we report that ES cells are responsive to alpha and beta interferons (IFNs). This property has been exploited for the development of inducible ES cell expression vectors, using the promoter of the human IFN-inducible gene, 6-16. The properties of these vectors have been analyzed in both transiently and stably transfected ES cells. Expression was minimal or absent in unstimulated ES cells, could be stimulated up to 100-fold by treatment of the cells with IFN, and increased in linear fashion with increasing levels of IFN. High levels of induced expression were maintained for extended periods of time in the continuous presence of the inducing signal or following a 12-h pulse with IFN. Treatment of ES cells with IFN did not affect their growth or differentiation in vitro or compromise their developmental potential. This combination of features makes the 6-16-based expression vectors suitable for the functional analysis of developmental control control genes in ES cells.


Reproduction ◽  
2021 ◽  
Vol 161 (4) ◽  
pp. 353-363
Author(s):  
Mun-Hyeong Lee ◽  
Pil-Soo Jeong ◽  
Bo-Woong Sim ◽  
Hyo-Gu Kang ◽  
Min Ju Kim ◽  
...  

In the mammalian female reproductive tract, physiological oxygen tension is lower than that of the atmosphere. Therefore, to mimic in vivo conditions during in vitro culture (IVC) of mammalian early embryos, 5% oxygen has been extensively used instead of 20%. However, the potential effect of hypoxia on the yield of early embryos with high developmental competence remains unknown or controversial, especially in pigs. In the present study, we examined the effects of low oxygen tension under different oxygen tension levels on early developmental competence of parthenogenetically activated (PA) and in vitro-fertilized (IVF) porcine embryos. Unlike the 5% and 20% oxygen groups, exposure of PA embryos to 1% oxygen tension, especially in early-phase IVC (0–2 days), greatly decreased several developmental competence parameters including blastocyst formation rate, blastocyst size, total cell number, inner cell mass (ICM) to trophectoderm (TE) ratio, and cellular survival rate. In contrast, 1% oxygen tension did not affect developmental parameters during the middle (2–4 days) and late phases (4–6 days) of IVC. Interestingly, induction of autophagy by rapamycin treatment markedly restored the developmental parameters of PA and IVF embryos cultured with 1% oxygen tension during early-phase IVC, to meet the levels of the other groups. Together, these results suggest that the early development of porcine embryos depends on crosstalk between oxygen tension and autophagy. Future studies of this relationship should explore the developmental events governing early embryonic development to produce embryos with high developmental competence in vitro.


Reproduction ◽  
2015 ◽  
Vol 150 (1) ◽  
pp. 31-41 ◽  
Author(s):  
Young-Ho Choi ◽  
Pablo Ross ◽  
Isabel C Velez ◽  
B Macías-García ◽  
Fernando L Riera ◽  
...  

Equine embryos developin vitroin the presence of high glucose concentrations, but little is known about their requirements for development. We evaluated the effect of glucose concentrations in medium on blastocyst development after ICSI. In experiment 1, there were no significant differences in rates of blastocyst formation among embryos cultured in our standard medium (DMEM/F-12), which contained >16 mM glucose, and those cultured in a minimal-glucose embryo culture medium (<1 mM; Global medium, GB), with either 0 added glucose for the first 5 days, then 20 mM (0-20) or 20 mM for the entire culture period (20-20). In experiment 2, there were no significant differences in the rates of blastocyst development (31–46%) for embryos cultured in four glucose treatments in GB (0-10, 0-20, 5-10, or 5-20). Blastocysts were evaluated by immunofluorescence for lineage-specific markers. All cells stained positively forPOU5F1. An inner cluster of cells was identified that included presumptive primitive endoderm cells (GATA6-positive) and presumptive epiblast (EPI) cells. The 5-20 treatment resulted in a significantly lower number of presumptive EPI-lineage cells than the 0-20 treatment did.GATA6-positive cells appeared to be allocated to the primitive endoderm independent of the formation of an inner cell mass, as was previously hypothesized for equine embryos. These data demonstrate that equine blastocyst development is not dependent on high glucose concentrations during early culture; rather, environmental glucose may affect cell allocation. They also present the first analysis of cell lineage allocation inin vitro-fertilized equine blastocysts. These findings expand our understanding of the factors that affect embryo development in the horse.


Development ◽  
1982 ◽  
Vol 68 (1) ◽  
pp. 175-198
Author(s):  
R. L. Gardner

The technique of injecting genetically labelled cells into blastocysts was used in an attempt to determine whether the parietal and visceral endoderm originate from the same or different cell populations in the early embryo. When the developmental potential of 5th day primitive ectoderm and primitive endoderm cells was compared thus, only the latter were found to colonize the extraembryonic endoderm. Furthermore, single primitive endoderm cells yielded unequivocal colonization of both the parietal and the visceral endoderm in a proportion of chimaeras. However, in the majority of primitive endodermal chimaeras, donor cells were detected in the parietal endoderm only, cases of exclusively visceral colonization being rare. Visceral endoderm cells from 6th and 7th day post-implantation embryos also exhibited a striking tendency to contribute exclusively to the parietal endoderm following blastocyst injection. The above findings lend no support to a recent proposal that parietal and visceral endoderm are derived from different populations of inner cell mass cells. Rather, they suggest that the two extraembryonic endoderm layers originate from a common pool of primitive endoderm cells whose direction of differentiation depends on their interactions with non-endodermal cells.


2006 ◽  
Vol 18 (2) ◽  
pp. 197 ◽  
Author(s):  
B. S. Song ◽  
J. S. Kim ◽  
D. B. Koo ◽  
J. S. Park ◽  
K. K. Lee ◽  
...  

The microenvironment of the follopian tube, in which the oviductal fluid contains a variety of cytokines and growth factors, affects pre-implantation development of fertilized embryos in mammals. Prostaglandin I2 (PGI2, prostacyclin) exists in oviductal fluid and is synthesized from arachidonic acid by prostacyclin synthetase. PGI2 also enhances the implantation rate of mouse embryos. In this study, the effect of PGI2 analog on the development of bovine embryos was examined. Bovine cumulus oocytes complexes (COCs) were matured in TCM-199 medium supplemented with 10 IU/mL pregnant mare serum gonadotropin (PMSG), 10 IU/mL hCG, and 10 ng/mL epidermal growth factor (EGF) at 39�C, 5% CO2 in air for 20-22 h. Following in vitro maturation, COCs were fertilized in Fert-TALP medium containing 0.6% BSA using frozen semen. Also, oocytes matured in vitro were enucleated, individually reconstructed with bESF cells, fused, and then activated by treatment with 5 �M ionomycin for 5 min and 2 mM 6-DMAP for 4 h. In vitro-fertilized (IVF) and nuclear-transferred (NT) eggs were cultured in 50 ��L drops of CR1-aa medium supplemented with 0.3% BSA in the absence or presence of 1 �M PGI2 analog at 39�C, 5% CO2 in air, respectively. At 3 days of culture, cleaved embryos were further cultured in the same culture media supplemented with 10% FBS for 4 days. Allocations of blastocysts to inner cell mass (ICM) and trophoblast (TE) cells were investigated to assess embryo quality. All experiments were repeated more than three times. All data were analyzed by using the Duncan test of ANOVA by the Statistical Analysis System (SAS Institute, Inc., Cary, NC, USA) and numbers of nuclei in blastocysts were expressed as mean � SE. No difference was detected in the cleaved rate of the eggs between the treated- and nontreated groups. IVF zygotes treated with PGI2 analog represented a higher developmental rate (33%, 122/418) to the blastocyst stage than nontreated controls (24%, 107/456) (P < 0.05). Among IVF-derived blastocysts, interestingly, the proportion (46%, 84/181) of expanded blastocysts was significantly higher in the PGI2 analog-treated group compared with that in the nontreated group (28%, 46/164). The number of nuclei in (165 � 6.1, n = 15) in blastocysts in the PGI2 analog-treated group was higher than that (146.12 � 5.7, n = 18) in the nontreated group (P < 0.05). No difference was detected in the ratio of ICM to total cells between PGI2 analog-treated (42.0 � 3.0%) and nontreated groups (41.9 � 2.9%). Like the IVF embryos, NT embryos in the PGI2 analog-treated group showed a higher in vitro developmental rate (33.6%, 43/128) than the nontreated embryos (24.2%, 32/132) (P < 0.05). Our results indicate that PGI2 analog improves the kinetics of embryo development in cattle.


2017 ◽  
Vol 29 (1) ◽  
pp. 182
Author(s):  
S. M. Bernal-Ulloa ◽  
A. Lucas-Hahn ◽  
P. Aldag ◽  
D. Herrmann ◽  
U. Baulain ◽  
...  

Oocyte culture in the presence of the nonspecific competitive phosphodiesterase inhibitor caffeine has been reported to increase developmental capacity of oocytes in different mammalian species. Here, we evaluated the effects of caffeine supplementation during the final phase of in vitro maturation (IVM) on developmental rates and blastocyst cell numbers. Bovine ovaries were collected from a local abattoir. A total of 1142 cumulus-oocyte-complexes were obtained by slicing. Cumulus-oocyte complexes were either in vitro matured for 24 h (Standard) or matured for 20 h followed by additional culture for 6 h in fresh IVM medium supplemented with 10 mM caffeine (Caffeine 6 h). In vitro fertilization was performed for 19 h using frozen-thawed sperm from 2 different bulls. After IVF, presumptive zygotes were cultured in vitro for 8 days until the blastocyst stage. Cleavage and blastocyst rates were evaluated 3 and 8 days after IVF, respectively. Expanded blastocysts from the different treatments were submitted to differential staining. SAS/STAT software (SAS Institute Inc., Cary, NC, USA) was used to evaluate cleavage and blastocyst rates using the Glimmix procedure and blastocyst cell numbers were compared using the linear model procedure. Cleavage rates were lower using caffeine for bull B and blastocyst production decreased for bull A. Caffeine treatment increased inner cell mass (ICM) number for bull B and decreased trophectoderm (TE) and total cell numbers for bull A. However, similar TE and total cells were obtained for bull B (Table 1; P < 0.05). Results show that developmental competence can be affected by caffeine supplementation at the final phase of IVM probably due to oocyte-sperm interaction changes. Table 1. In vitro developmental competence of oocytes cultured with caffeine at the end of IVM


2019 ◽  
Vol 31 (12) ◽  
pp. 1758 ◽  
Author(s):  
Elaine M. Carnevale ◽  
Elizabeth S. Metcalf

Intracytoplasmic sperm injection (ICSI) is used to produce equine embryos invitro. The speed of embryo development invitro is roughly equivalent to what has been described for embryos produced invivo. Morphological evaluations of ICSI-produced embryos are complicated by the presence of debris and the dark nature of equine embryo cytoplasm. Morulas and early blastocysts produced invitro appear similar to those produced invivo. However, with expansion of the blastocyst, distinct differences are observed compared with uterine embryos. In culture, embryos do not undergo full expansion and thinning of the zona pellucida (ZP) or capsule formation. Cells of the inner cell mass (ICM) are dispersed, in contrast with the differentiated trophoblast and ICM observed in embryos collected from uteri. As blastocysts expand invitro, embryo cells often escape the ZP as organised or disorganised extrusions of cells, probably through the hole incurred during ICSI. Quality assessment of invitro-produced early stage equine embryos is in its infancy, because limited information is available regarding the relationship between morphology and developmental competence. Early embryo development invivo is reviewed in this paper, with comparisons made to embryo development invitro and clinical assessments from a laboratory performing commercial ICSI for &gt;15 years.


2017 ◽  
Vol 29 (7) ◽  
pp. 1392 ◽  
Author(s):  
Dandan Liu ◽  
Guolong Mo ◽  
Yong Tao ◽  
Hongmei Wang ◽  
X. Johné Liu

Mouse ovaries exhibit a peri-ovulatory rise of ornithine decarboxylase and its product putrescine concurrent with oocyte maturation. Older mice exhibit a deficiency of both the enzyme and putrescine. Peri-ovulatory putrescine supplementation in drinking water increases ovarian putrescine levels, reduces embryo resorption and increases live pups in older mice. However, it is unknown if putrescine acts in the ovaries to improve oocyte maturation. This study examined the impact of putrescine supplementation during oocyte in vitro maturation (IVM) on the developmental potential of aged oocytes. Cumulus–oocyte complexes from 9–12-month-old C57BL/6 mice were subjected to IVM with or without 0.5 mM putrescine, followed by in vitro fertilisation and culture to the blastocyst stage. Putrescine supplementation during IVM did not influence the proportion of oocyte maturation, fertilisation or blastocyst formation, but significantly increased blastocyst cell numbers (44.5 ± 1.9, compared with 36.5 ± 1.9 for control; P = 0.003). The putrescine group also had a significantly higher proportion of blastocysts with top-grade morphology (42.9%, compared with 26.1% for control; P = 0.041) and a greater proportion with octamer-binding transcription factor 4 (OCT4)-positive inner cell mass (38.3%, compared with 19.8% for control; P = 0.005). Therefore, putrescine supplementation during IVM improves egg quality of aged mice, providing proof of principle for possible application in human IVM procedures for older infertile women.


2004 ◽  
Vol 16 (2) ◽  
pp. 186
Author(s):  
J.O. Gjørret ◽  
P. Maddox-Hyttel

Regulation of apoptosis may be affected by factors during preimplantation development, and this is possibly related to embryo developmental potential. Here we investigate differences in the incidence of apoptotic nuclei in Day 7 bovine blastocysts produced by two different in vivo and three different in vitro methods. In vivo embryos were produced either by a regular superovulation procedure (reg group; n=29; Laurincik et al., 2003, Mol. Reprod. Dev. 65, 73–85), or by postponement of the LH surge (pp group; n=35; van de Leemput et al., 2001, Therio. 55, 573–592). In vitro embryos were derived from systems using either co-culture (cc group; n=30, Avery and Greve 2000, Mol. Reprod. Dev. 55, 438–445), or culture in synthetic oviduct fluid (SOF) with (S+group; n=35) or without serum (S− group; n=38; Holm et al., 1999, Theriogenology, 52, 683–700). Embryos were collected at approx. 168h post ovulation/insemination and subjected to chromatin staining and detection of DNA degradation by TUNEL reaction. The total number of nuclei, number of nuclei displaying apoptotic morphology (+M), number of nuclei displaying TUNEL reaction (+T), and number of nuclei displaying both markers simultaneously (M&amp;T) were scored according to J.O. Gjørret et al. (2003 Biol. Reprod. 69. in press). Only M&amp;T nuclei were regarded as apoptotic, and +M, +T, and apoptotic (M&amp;T) indices (%) were calculated for the trophoblast (tb), inner cell mass (i) and the total blastocysts (t) in each group. Significant differences were observed for all parameters when all groups were compared (ANOVA, P ranging from 0.024 to&lt;0.0001). Highest number of total nuclei were observed in the S+ group, whereas the lowest indices were observed in the pp group, which had significant lower indices in the i and t than in the reg., S+ and S− groups P&lt;0.05; Tukey’s post test for ANOVA). Highest indices were generally observed in the S− group. The results demonstrate that not only embryo cell numbers but also incidences of apoptotic markers are affected by the mode of production. However, in Day 7 bovine blastocysts high cell number is not consistent with a low incidence of apoptosis. Even though cell numbers appeared comparable in the two in vivo groups, their incidences of apoptosis were different, and the reg group displayed indices comparable to the in vitro groups, highlighting the importance of ovulation protocols when in vivo embryos are used as reference material in general. Table 1


2007 ◽  
Vol 19 (1) ◽  
pp. 144
Author(s):  
Y. U. Kim ◽  
D. P. Bhandari ◽  
M. S. Hossein ◽  
S. M. Park ◽  
E. Lee ◽  
...  

Insulin promotes the uptake of glucose and amino acids, and is beneficial for maturation of oocytes in vitro. Transferrin is an iron-transport protein and selenium is an essential trace element. Insulin-transferrin-selenium (ITS) together has been used in some in vitro maturation systems. The present study was designed to evaluate the effects of ITS in defined and porcine folicular fluid (pFF)-supplemented IVM medium on the glutathione (GSH) concentration, and on developmental competence after somatic cell nuclear transfer. ITS liquid media supplement (I-3146) was purchased from Sigma-Aldrich (St Louis, MO, USA). Basic IVM medium was TCM-199 supplemented with 10 ng mL-1 epidermal growth factor, 4 IU mL-1 pregnant mare serum gonadotropin (PMSG) and hCG and either 1% PVA (defined medium) or 10% pFF. Ten �g mL-1 insulin, 5.5 �g mL-1 transferrin, and 5 �g mL-1 selenium was used for the entire 44-h culture period. The GSH content of a gruop of 10 to 20 oocytes was determined by the dithionitrobezoic acid-glutathione disulfide (DTNB-GSSG) reductase recycling assay. Fetal fibroblasts were used as somatic cell donors and reconstructed embryos were cultured in mNCSU-23 medium for 168 h. Cleavage and blastocyst formation was observed at 48 h and 168 h, respectively. The quality of blastocysts was assessed by differential staining of the inner cell mass (ICM) and the trophectoderm (TE) cells. Each experiment was replicated for 5 times. The data were analyzed by one-way ANOVA, and Tukey was used as a posthoc test. The level of GSH production significantly varied in different culture conditions. The highest GSH concentration was observed in the pFF + ITS group (8.2 picomol/oocyte). A total of 116, 125, 126, and 120 reconstructed oocytes were cultured, and 10.1, 15.3, 17.2, and 21.8% blastocysts were observed for PVA, PVA + ITS, pFF, and pFF + ITS groups, respectively (P &lt; 0.05). The numbers of inner cell mass, trophrectoderm cells, and total cells were significantly higher in the pFF + ITS group compared with the other groups. The average number of total cells in blastocysts was 31.9 � 1.8, 43.1 � 3.5, 46.7 � 4.9, and 52.3 � 6.7 for PVA, PVA + ITS, pFF, and pFF + ITS groups, respectively (P &lt; 0.05). ITS supplement improved the developmental competence in both the defined and the pFF supplemented groups. We recommend supplementing porcine IVM medium with 10 �g mL-1 insulin, 5.5 �g mL-1 transferrin, and 5 �g mL-1 selenium.


Sign in / Sign up

Export Citation Format

Share Document